This past weekend Stratolaunch successfully completed its second series of taxi tests, reaching a speed of 40 knots (46 miles per hour) as it moved down the runway.

[I]n December Stratolaunch capped off the year with a successful low-speed taxi test. During the taxi, the vehicle reached a top speed of 28 miles per hour (45 kilometers per hour) as it headed down the runway. Following the test, Aircraft Program Manager George Brugg stated, “This was another exciting milestone for our team and the program. Our crew was able to demonstrate ground directional control with nose gear steering, and our brake systems were exercised successfully on the runway. Our first low-speed taxi test is a very important step toward first flight.”

Last weekend, Sratolaunch kicked off 2018 with two days of additional taxi tests. Most notably, the tests included reaching the maximum taxi speed of 40 knots (46 miles per hour). According to Allen, these tests allowed the team to “verify control responses.”

There is a tiny 35 second video of this last test at the link.

The article provides a lot of details about Stratolaunch and its future, including the suggestion that the giant airplane could become the main launch platform for Orbital ATK’s Pegasus rocket. Pegasus presently has only one launch listed on its manifest, using its L1011 Stargazer airplane.